Mining machine with a pivot structure for a mining head, gathering head and discharge conveyor boom

ABSTRACT

A continuous mining machine has a pivoting mining head and gathering head at the front of the machine and a pivoting discharge conveyor boom extending from the rear of the machine. The mining head, gathering head and conveyor boom pivot on a pivot structure about a common axis. The pivot structure has first and second upright pivot supporting members on the main frame of the mining machine which mount and secure a pivot means for the mining head and a pivot means for the gathering head and conveyor. Either the pivot means for the mining head or the pivot means for the gathering head and conveyor can be removed from the pivot structure while the other pivot means remains mounted and secured in the pivot structure.

United States Patent Munger Apr. 2, 1974 [75] Inventor: Fay E. Munger, Upper Arlington,

Ohio

[73] Assignee: Jeffrey Galion Inc., Columbus, Ohio [22] Filed: Dec. 7, 1972 [21] Appl. No.: 312,842

[52] US. Cl. 299/64, 299/76 [51] Int. Cl. E2lc 27/24 [58] Field of Search 299/6468, 299/75, 76, 57; 198/8, 9, 10

[56] References Cited UNITED STATES PATENTS 3,479,090 11/1969 McCracken 299/64 MINING MACHINE WITH A PIVOT STRUCTURE FOR A MINING HEAD, GATHERING HEAD AND DISCHARGE CONVEYOR BOOM Primary Examiner-Ernest R. Purser Attorney, Agent, or Firm-David Young [57] ABSTRACT A continuous mining machine has a pivoting mining head and gathering head at the front of the machine and a pivoting discharge conveyor boom extending from the rear of the machine. The mining head, gathering head and conveyor boom pivot on a pivot structure about a common axis. The pivot structure has first and second upright pivot supporting members on the main frame of the mining machine which mount and secure a pivot means for the mining head and a pivot means for the gathering head and conveyor. Either the pivot means for the mining head or the pivot means for the gathering head and conveyor can be removed from the pivot structure while the other pivot means remains mounted and secured in the pivot structure.

19 Claims, 5 Drawing Figures PAIENTEDAPR 2 m4 SHEET 2 OF 3 MINING MACHINE WITH A PIVOT STRUCTURE FOR A MINING HEAD, GATHERING HEAD AND DISCHARGE CONVEYOR BOOM BACKGROUND OF THE INVENTION 1. Field of the Invention The instant invention relates to mining machines, and more particularly to a pivot structure for a continuous mining machine on which the mining head, the gathering head and the conveyor boom are pivotally supported on a common axis.

2. Description of the Prior Art A typical continuous mining machine has a mining head at the front end for cutting and breaking the material from the mine face, a gathering head below the mining head to collect the mined material, and a conveyor which receives the mined material and conveys it to the rear of the mining machine from which the mined material is discharged to a haulage vehicle or other equipment which takes the material away from the place of the mining operation. The mining head, the gathering head, and the conveyor are pivotally supported on the mining machine main frame for upward and downward movement for adjustment of the position of each of these elements of the machine.

Such a continuous mining machine is described in the patent to Bergmann, U.S. Pat. No. 3,307,879, Mar. 7, 1967. In this patent, the gathering head and the conveyor boom are pivotally mounted on a common axis near the front of a turntable on the main frame of the mining machine, and the position of each may be adjusted upwardly and downwardly. The mining head is pivotally mounted at the rear of the turntable on another axis for independent upward and downward movement to adjust the position of the mining head.

A continuous mining machine having a pivot structure which supports the mining head, the gathering head and the conveyor boom for independent movement upwardly and downwardly about a common axis is described in the patent to McCracken, U.S. Pat. No. 3,479,090, Nov. 18, 1969, and assigned to the same assignee as this patent application. The pivot structure in the McCracken patent has one upstanding pivot support member on the main frame at each side of the machine. A pivot element projects inwardly through an aperture in each pivot support member. The mining head is supported on the pivot elements and can be moved upwardly and downwardly about the axis of the pivot elements. The gathering head is supported on pivot elements that are placed within the pivot elements for the mining head, and the gathering head can be moved upwardly and downwardly about the axis of its pivot elements. The conveyor boom is supported by a pivot pin that extends through the pivot elements for the mining head and for the gathering head, and the conveyor boom can be moved upwardly and downwardly about the axis of the pivot pin. The pivot elements for the mining head and for the gathering head and the pivot pin for the conveyor boom are coaxial.

SUMMARY OF THE INVENTION In accordance with this invention, the continuous mining machine has a pivot structure for supporting the mining head, the gathering head and the conveyor boom, that comprises inner and outer upright pivot support members at each side of the machine main frame to pivotally support each of the mining head, the gathering head and the conveyor boom for movement upwardly and downwardly about a common axis. There is a pivot element for the mining head that is mounted in and secured to an outer pivot support member at each side of the main frame. There is another pivot element that is mounted in and secured to an inner pivot support member at each side of the machine main frame, to pivotally support the gathering head. A pivot pin extends through the gathering head pivot elements and is held by the latter, and the pivot pin pivotally supports the conveyor boom.

The pivot element for the mining head is mounted in the pivot structure independently of the pivot element for the gathering head and the pivot pin for the conveyor. Thus the mining head and its pivot structure may be disassembled separately and independently from the gathering head and the conveyor boom. Likewise, the gathering head and the conveyor boom and their pivot structure may be disassembled separately and indepen dently from the mining head. It is necessary to disassemble parts of the mining machine in order to reduce it to several components that are smaller than the total machine in order to facilitate handling the machine, and moving it in shipment or from place to place in the mine. Also, in the normal course of maintenance, the components of the machine need to be disassembled for servicing and replacement of parts. The pivot structure of this invention facilitates such disassembly and is particularly advantageous in handling the machine in the confined and limited space that is available in an underground mining operation.

Accordingly, it is an object of this invention to provide a mining machine with an improved pivot structure for pivotally supporting the mining head, the gathering head, and the conveyor on the main frame of the machine.

It is also an object of the invention to provide an improved pivot structure in a mining machine for the mining head, the gathering head and the conveyor, in which each of these components is independently adjustable upwardly and downwardly by pivotal movement thereof about a common axis.

It is a further object of the invention to provide a mining machine with an improved pivot structure for the mining head, the gathering head and the conveyor in which the mining head is pivotally supported on pivot elements that are separate from the gathering head and the conveyor, and the gathering head and the conveyor are pivotally supported on pivot elements that are separate from the mining head.

It is still another object of the invention to provide an improved pivot structure in a mining machine, in which the mining head, the gathering head and the conveyor are pivotally supported for adjustment of their positions, and the mining head may be disassembled from the mining machine and the pivot structure separately and independently of the gathering head and the conveyor, and similarly, the gathering head and the conveyor may be disassembled from the mining machine and the pivot structure separately and independently of the mining head.

It is yet another object of the invention to provide an improved pivot structure in a mining machine for the mining head, the gathering head and the conveyor which provides a substantial and rigid support on the machine main frame for these components and permits them to be adjusted upwardly and downwardly independently of one another.

It is a further object of the invention to provide an improved pivot structure in a mining machine for the mining head, the gathering head and the conveyor that makes it easier to disassemble these components of the machine in order to facilitate handling and servicing of the mining machine and its components.

Other objects of the invention will appear hereinafter, the novel features and combinations being set forth in the appended claims.

DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevational view of a mining machine incorporating the pivot structure of this invention.

FIG. 2 is a plan view of the mining machine shown in FIG. 1.

FIG. 3 is a perspective view of a portion of the main frame of the mining machine shown in FIG. 1.

FIG. 4 is an enlarged elevational view of a portion of the structure shown in FIG. 1.

FIG. 5 is a sectional view taken along the line 5-5 in FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENT A continuous mining machine with the improved pivot structure 11 of this invention is illustrated in FIGS. 1 and 2 of the drawings. The mining machine 10 has a mining head 12 with a rotary cutting and breaking drum 13 for removing material from a mine face. Endless crawler traction treads 14 at each side of the main frame 15 support the mining machine 10 on the mine floor and propel the mining machine 10 and the mining head 12 into the mine face.

The mining head 12 has a boom 16 that extends forwardly to support the rotary cutting and breaking drum 13 at the front end of the mining machine 10. The boom 16 has rearwardly extending spaced arms 17,17 which are connected by a lateral element 18. The arms 17,17 extend rearwardly to the pivot structure 11 and are supported on the latter. The mining head 12 has a plurality of spirally arranged cutter bits 19 and cutting chains 20,20 for cutting and breaking material from the mine face.

The mining head 12 is driven by electric motors 21,22 which are on opposite sides of the main frame 15. The motors 21,22 drive gear cases 23,24, first universal shafts 25,25, second universal shafts 26,26 and input gear cases 27,27, which are on the mining head 12 and drivingly connect to the rotary cutting and breaking drum 13, to drive the latter. The mining head 12 is moved upwardly and downwardly by hydraulic cylinders 30,30, pivotally attached at their lower ends to clevises 31,31 on the main frame 15 (See FIG. 3) and at their upper ends to the boom 16.

A gathering head 32 is at the forward end of the mining machine 10, beneath the mining head 12, and is pivotally supported on the pivot structure 11. Two gathering arms 33,33 on the gathering head 32 gather the mined material and sweep the material in toward the center of the gathering head 32 onto an endless chain and flight conveyor 34. g

The gathering arms 33,33 on the gathering head 32 are driven by motor 22 through motor gear case 24, universal shaft 35, and gear case 36, which drivingly connects to the gathering arms 33,33. The gathering head 32 may be raised and lowered by hydraulic cylinders 37,37, which are pivotally attached at their lower ends to clevises 38,38 on the main frame 15 in order to adjust the position of the gathering head 32 to follow the contour of the mine floor.

The endless chain and flight conveyor 34 extends longitudinally through the mining machine 10, from the gathering head 32 to the rear end of a discharge conveyor boom 39, which is pivotally supported on the pivot structure 1 l. The conveyor boom 39 is moved upwardly and downwardly about the axis of the pivot structure 11 by hydraulic cylinders 40,40, at opposite sides of the main frame 15, The rear extension of the conveyor boom 39 may be moved to one side or the other of the mining machine 10 by a double-acting hydraulic cylinder 41. This permits adjustment of the position of the conveyor boom 39 to discharge the mined material to a haulage vehicle or other equipment for removing the mined material from the mining place.

The gathering head 32 includes a portion of a conveyor bed 42, partially illustrated by broken lines in FIG. 4, which portion extends from a well in the forward part of the gathering head 32 back to the pivot structure 11. The remaining portion of the conveyor bed 42 is formed in the discharge conveyor boom 39, and extends from the pivot structure 11 rearwardly. Mined material is moved along the conveyor bed 42 from the front of the mining machine 10 to the rear thereof by the chain and flight conveyor 34.

FIGS. 3, 4 and 5 illustrate the detailsof the pivot structure 11, which is the same on each side of the mining machine 10, except that the elements are oppositely disposed. Therefore, this description will proceed with respect to the pivot structure 1 l on one side only of the mining machine 10, with the understanding that the description applies equally to the pivot structure 11 on the other side of the mining machine 10.

An outer upright pivot support member 46 is affixed to the main frame 15 of the mining machine 10, as by welding, at one side thereof. An inner upright pivot support member 47 is affixed to the main frame 15, as by welding, at one side, but spaced laterally inwardly from the pivot support member 46. The pivot support members 46,47 are placed alongside each other in lateral adjustment. A lateral frame member 48 extends between and is secured to support members 46,47 at the rear tops thereof in order to strengthen and to rigidify the pivot structure 11.

The pivot support member 46 has a large circular aperture 49 machined therein. A cylindrical pivot element 50 extends through the aperture 49. The base portion 51 of the pivot element 50 in the aperture 49 is formed with an outer diameter that closely fits the diameter of the aperture 49, so as to firmly seat the cylindrical pivot element 50 on the support member 46. The pivot element 50 continues-from the base portion 51 in a reduced diameter cylindrical portion52 that is seated in a shoulder 53 machined in the inner upright pivot support member 47. The reduced diameter portion 52 of the pivot element 50 fits freely through the aperture 49, and fits closely to the diameter of the shoulder 53, so that the end of the pivot element is firmly seated on the shoulder 53. l

The outer end of pivot element 50 has opposite radial flanges 54,54 that lay against the outer surface 55 of pivot support member 46. A plurality of bolts 56 pass through bores 57 drilled in the flanges 54,54 and fixedly secure the pivot element 50 to the member 46.

A threaded bore 58 is machined in each flange 54, and is used to receive a jackscrew to withdraw the pivot element 50 from the pivot structure 11 after the several bolts 56 have been withdrawn.

Arms 17,17 of the mining head 12 extend rearwardly to the pivot structure 11. Each arm 17 has a bore 59, with a bushing 60 that has a radially extending annular flange 61 that lays against the arm 17 around the bore 59. A pin 62 extends through a bore 63 in the flange 61 and into an opening 64 in the side arm 17, to prevent relative rotation between the bushing 60 and the side arm 17.

The reduced diameter portion 52 of the pivot element 50 extends through the bore 67 of the bushing 60 to support the side arm 17 in the pivot structure 11. The bushing 60 and the side arm 17 pivot together about the axis of the pivot element 50.

The inner upright pivot support member 47 has a circular aperture 68 machined therein, and this is coaxial with the annular shoulder 53 and the aperture 49 in the pivot support member 46. A bushing 69 is seated within the aperture 68. The bushing 69 has a radial flange 70 that lays against a surface 71 machined on the inner face of the pivot support member 47.

A cylindrical pivot element 72 is seated in the bore 73 of the bushing 69 and fits closely therein. A reduced diameter part 74 of tapered boss 75 extends inwardly from the pivot element 72, and is formed as a truncated cone of decreasing diameter. The part 74 provides a tapered cylindrical part to which the gathering head 32 is attached with a press fit. The gathering head 32 is formed with arms 76,76, one at each side, that extend rearwardly to the pivot structure 11, and each arm 76 has a truncated conical aperture 77 that mates with the oppositely conical part 75 to make a press fit of the gathering head arms 76,76 on the pivot element 72, and prevents relative movement between the gathering head 32 and the pivot element 72.

A plurality of bolts 78 secure the pivot element 72 and the gathering head arm 76 together. Each bolt 78 has a cylindrical shank 79 that extends freely through a hole 80 in the pivot element 72, and the end of the bolt 78 is formed with threads that is turned into a threaded hole 81 in the gathering head arm 76. The bolts 78 secure the gathering head 32 to the cylindrical pivot element 72 for pivotal movement of the gathering head 32 about the axis of the pivot structure 11.

The pivot element 72 has an axial bore 82 machined therein. One end of a pivot pin 83 is seated in the bore 82. The pivot pin 83 extends through a bushing 84 seated against a shoulder 85 formed near the end of the bore 86 of the sleeve 87 of the conveyor boom 39. The sleeve 87 and the conveyor boom 39 pivot on the pivot pin 83. The pivot pin 83 is held in fixed position within the bore 82 by an end cap 88 which is secured to the pivot element 72 by the bolts 78.

The pivot element 50, the pivot element 72 and the pivot pin 83 are all mounted in the pivot structure 11 on a common axis. Consequently, the mining head 12, the gathering head 32 and the conveyor boom 39 are supported on the pivot structure 11 for pivotal movement about a common axis.

The conveyor boom 39 can be removed from the pivot structure 11 and from the machine by withdrawing the pivot pin 83 through the bore 82 of the pivot element 72, after the end cap 88 has been taken off. The pivot pin 83 is struck from one end and pushed through the bore 82 at the opposite end. The pivot pin 83 passes freely through the bore 89 of the pivot element 50, which is substantially larger. Thus, the discharge conveyor boom 39 can be removed without disturbing the cylindrical pivot element 72, the gathering head 32, the pivot element 50, or the mining head 12.

The gathering head 32 can be removed from the pivot structure 11 following removal of the pivot pin 83. The bore 89 in the pivot element 50 is larger than the outside diameter of the pivot element 72. Therefore, after the bolts 78 have been removed, the cylindrical pivot element 72 can be laterally withdrawn into the bore 89 and separated from the gathering head 32 to permit the latter to be removed from the pivot structure 11 and from the main frame 15. The gathering head 32 is removed from the pivot structure 1 1 without disturbing the outer pivot element 50 and the mining head 12.

It is sometimes necessary to remove the mining head 12. The pivot structure 11 provides a convenient means by which the mining head 12 can be removed without disturbing the gathering head 32 or the conveyor boom 39. To remove the mining head 12, the bolts 56 are withdrawn to release the pivot element 50. Jackscrews can be put in the threaded holes 58 to withdraw the pivot element 50 from the pivot support 46. After the pivot element 50 has been withdrawn, the mining head 12 can be removed.

Appropriate fittings 90 and passages are provided for lubricating bearing surfaces; such as between the pivot element 50 and the bushing 60 which pivots about its reduced diameter portion 52, the cylindrical pivot element 72 and the bushing 69 within which it rotates, and the pivot pin 83 and the bushing 8% within which it pivots. The fittings 90 and lubricant passages are shown in FIG. 5.

It can be seen that the pivot structure of the instant invention provides a pivot element for the mining head and independent pivot elements for the gathering head and for the discharge conveyor boom. Either the mining head pivot element or the gathering head and discharge conveyor boom pivot elements can be removed from the pivot structure, independently of each other,

such that the several components of the mining machine can be removed as hereinbefore described.

Obviously, those skilled in the art may make various changes in the details and arrangements of parts, without departing from the spirit and scope of the invention as defined by the claims hereto appended, and applicant, therefore, wishes not to be restricted to the precise construction herein disclosed.

Having thus described and shown an embodiment of the invention, what is desired to secure by Letters Patent of the United States is:

l. A mining machine having a mining head at the front end thereof for cutting and breaking material from a mine face, a gathering head at the front end of the mining machine and below the mining head for gathering the material that is cut and broken from the mine face, a conveyor that extends from the gathering head rearwardly through the mining machine to receive the mined material from the gathering head and to convey the mined material to the rear of the mining ma- I frame for the mining machine, propulsion means on the main frame to advance the mining machine into the mine face, a pivot structure on said main frame for mounting and supporting the mining head, the gathering head, and the conveyor on the main frame for pivotal movement of each of the mining head, the gathering head and the conveyor on said pivot structure and about a common transverse axis, said pivot structure including first pivot means for the mining head, second pivot means for the gathering head and for the conveyor, means to independently mount and secure said first pivot means and said second pivot means in said pivot structure and to permit either of said first pivot means or said second pivot means to be removed from the pivot structure while the other pivot means remains mounted and secured in the pivot structure.

2. A mining machine as recited in claim 1, in which said means to independently mount and secure said first pivot means and said second pivot means includes a first upright pivot supporting member on said main frame for the first pivot means, and a second upright pivot supporting member on said main frame for the second pivot means.

3. A mining machine as recited in claim 2, in which said first upright pivot supporting member and said second upright pivot supporting member are positioned alongside each other, a circular opening in said first upright pivot supporting member to receive said first pivot means, a circular opening in said second upright pivot supporting member to receive said second pivot means, said circular openings being coaxial 'on said.

said first upright pivot supporting member and said second upright pivot supporting member are disposed at one side of said main frame and are laterally spaced one from the other, said first pivot means comprises a cylindrical pivot element that extends through said first pivot supporting member and is seated on said second pivot supporting member, said mining head includes a boom with a circular opening that is engaged with said cylindrical pivot element between the first and second pivot supporting members.

5. A mining machine as recited in claim 3 in' which said first upright pivot supporting member and said second upright pivot supporting member are disposed at one side of said main frame, said second pivot means comprises a cylindrical pivot element that extends through said second pivot supporting member and has a projection towards the center of said main frame, a pivot pin extending through said cylindrical pivot element and beyond the projection thereof towards the center of the main frame, means to engage said gathering head with said second pivot means projection, and means to engage said conveyor with said pivot pin independently of said cylindrical pivot element projection and said gathering head.

6. A mining machine as recited in claim 3 in which said first upright pivot supporting member and said second upright pivot supporting member are disposed at one side of the main frame and are laterally spaced one from the other, said first pivot'means comprises a cylindrical pivot element that extends through said first pivot supporting member to between said first and second pivot supporting members to pivotally engage the mining head, said second pivot means comprises a cylindrical pivot element that extends through said second pivot supporting member and has a projection towards the center of said main frame to engage the gathering head, the first said cylindrical pivot element having an internal diameter that is greater than the diameter of thesecond said cylindrical pivot means to permit the second cylindrical pivot means to be withdrawn through the first said cylindrical pivot element from said second pivot supporting member. l

7. A mining machine as recited in claim 6 in which said second pivot means includesa pivot pin extending through the second said cylindrical pivot element towards the center of the main frame to pivotally engage said conveyor independently of said gathering head and the second said cylindrical pivot element.

8. A mining machine as recited in claim 7, the first said cylindrical pivot element is fixedly secured to said first pivot supporting member, the second said cylindrical pivot element is fixedly secured to said gathering head, and means to pivotally support the second said cylindrical pivot element in said second pivotsupport member.

9. A mining machine as recited in claim 8, said pivot pin is fixedly secured to the second said cylindrical pivot element, and means between said pivot pin and said conveyor to pivotally support the conveyor on the pivot pin.

10. A mining machine as recited in claim 6 including means disposed between the main frame and said mining head to move the mining head upwardly and downwardly by pivoting the mining head about said common transverse axis, means disposed between the main frame and said gathering head to move the gathering head upwardly and downwardly by pivoting the gathering head about said common transverse axis, and means disposed between the main frame and said conveyor to move the conveyor upwardly and downwardly by pivoting the conveyor about said common transverse axis.

11. A mining machine having a mining head at the front end thereof for cutting and breaking material from a mine face, a gathering head at the front end of the mining machine and below the mining head for gathering the material that is cut and broken from the mine face, a conveyor that extends from the gathering head rearwardly through the mining machine to receive the mined material from the gathering head and to convey the mined material to the rear of the mining machine and to discharge the material therefrom, a main frame for the mining machine, propulsion means on the main frame to advance the mining machine into the mine face, a pivot structure on said main frame for mounting and supporting the mining head, the gathering head and the conveyor on the main frame for pivotal movement of each of the mining head, the gathering head and the conveyor on said pivot structure and about a common transverse axis, said pivot structure including a pair of outer upright pivot supporting members on said main frame, first pivot means for said mining head which engage said outer upright pivot supporting members, said pivot structure including a pair of inner upright pivot supporting members on said main frame, second pivot means for said gathering head and said conveyor which engage said inner upright pivot supporting members, said first pivot means and said second pivot means have a common axis, and either said first pivot means or said second pivot means may be removed from said pivot structure while the other pivot means remains engaged with the pivot structure.

12. A mining machine as recited in claim 11, in which each of said outer upright pivot supporting members has a circular opening to receive said first pivot means, each of said inner upright pivot supporting members has a circular opening to receive said second pivot means and said circular openings in said outer upright pivot supporting members and said inner upright pivot supporting members are coaxial on said common axis.

13. A mining machine as recited in claim 12, in which said first pivot means includes a pair of cylindrical pivot elements, each of said cylindrical pivot elements extends inwardly through the circular opening in an outer upright pivot member and is supported at one end on an inner upright pivot support member, said mining head including a boom with a pair of parallel arms, and each of said arms has a circular opening which engages one of said cylindrical pivot elements between an outer upright pivot support member and an inner upright pivot support member.

14. A mining machine as recited in claim 13, in which each of said cylindrical pivot elements is rigidly secured to an outer upright pivot support member, and including means to pivotally mount said boom arms on said pair of cylindrical pivot elements.

15. A mining machine as recited in claim 13, in which said second pivot means includes a pair of cylindrical pivot elements, means to pivotally mount each of the second said cylindrical pivot elements in a circular opening in one of said inner upright pivot support members, and means to attach said gathering head to each of the second said cylindrical pivot elements.

16. A mining machine as recited in claim 15, in which said second pivot means includes a pivot pin, each of the second said cylindrical pivot elements includes a circular bore to receive one end of said pivot pin, and means to pivotally mount said conveyor on said pivot pin independently of said gathering head and the second said cylindrical pivot elements.

17. A mining machine as recited in claim 16, in which each of the first said cylindrical pivot elements has a bore which is coaxial with the second said cylindrical pivot elements, and said bore in each of the first said cylindrical pivot elements is greater in diameter than said pivot pin to permit said pivot pin to be withdrawn from the pivot structure through one of the second said cylindrical pivot elements and one of the first said cylindrical pivot elements and to permit said conveyor to be removed from the pivot structure independently of the removal of said mining head, said gathering head, said first pivot means and the second said cylindrical pivot elements.

18. A mining machine as recited in claim 17, in which said bore in each of the first said cylindrical pivot elements is greater in diameter than the second said cylindrical pivot elements to permit each of the second said cylindrical pivot elements to be withdrawn from the pivot structure through one of the first said cylindrical pivot elements and to permit said gathering head to be removed from the pivot structure following the removal of said pivot pin, independently of the removal of said mining head and said first pivot means.

19. A mining machine as recited in claim 11, in which said outer upright pivot supporting members are positioned on opposite sides of the center of said main frame, said inner upright pivot supporting members are positioned on opposite sides of the center of said main frame, and a lateral member joins one of said inner and outer upright pivot supporting members on the same side of the main frame. 

1. A mining machine having a mining head at the front end thereof for cutting and breaking material from a mine face, a gathering head at the front end of the mining machine and below the mining head for gathering the material that is cut and broken from the mine face, a conveyor that extends from the gathering head rearwardly through the mining machine to receive the mined material from the gathering head and to convey the mined material to the rear of the mining machine and to discharge the material therefrom, a main frame for the mining machine, propulsion means on the main frame to advance the mining machine into the mine face, a pivot structure on said main frame for mounting and supporting the mining head, the gathering head, and the conveyor on the main frame for pivotal movement of each of the mining head, the gathering head and the conveyor on said pivot structure and about a common transverse axis, said pivot structure including first pivot means for the mining head, second pivot means for the gathering head and for the conveyor, means to independently mount and secure said first pivot means and said second pivot means in said pivot structure and to permit either of said first pivot means or said second pivot means to be removed from the pivot structure while the other pivot means remains mounted and secured in the pivot structure.
 2. A mining machine as recited in claim 1, in which said means to independently mount and secure said first pivot means and said second pivot means includes a first upright pivot supporting member on said main frame for the first pivot means, and a second upright pivot supporting member on said main frame for the second pivot means.
 3. A mining machine as recited in claim 2, in which said first upright pivot supporting member and said second upright pivot supporting member are positioned alongside each other, a circular opening in said first upright pivot supporting member to receive said first pivot means, a circular opening in said second upright pivot supporting member to receive said second pivot means, said circular openings being coaxial on said common transverse axis.
 4. A mining machine as recited in claim 3 in which said first upright pivot supporting member and said second upright pivot supporting member are disposed at one side of said main frame and are laterally spaced one from the other, said first pivot means comprises a cylindrical pivot element that extends through said first pivot supporting member and is seated on said second pivot supporting member, said mining head includes a boom with a circular opening that is engaged with said cylindrical pivot element between the first and second pivot supporting members.
 5. A mining machine as recited in claim 3 in which said first upright pivot supporting member and said second upright pivot supporting member are disposed at one side of said main frame, said second pivot means comprises a cylindrical pivot element that extends through said second pivot supporting member and has a projection towards the center of said main frame, a pivot pin extending through said cylindrical pivot element and beyond the projection thereof towards the center of the main frame, means to engage said gathering head with said second pivot means projection, and means to engage said conveyor with said pivot pin independently of said cylindrical pivot element projection and said gathering head.
 6. A mining machIne as recited in claim 3 in which said first upright pivot supporting member and said second upright pivot supporting member are disposed at one side of the main frame and are laterally spaced one from the other, said first pivot means comprises a cylindrical pivot element that extends through said first pivot supporting member to between said first and second pivot supporting members to pivotally engage the mining head, said second pivot means comprises a cylindrical pivot element that extends through said second pivot supporting member and has a projection towards the center of said main frame to engage the gathering head, the first said cylindrical pivot element having an internal diameter that is greater than the diameter of the second said cylindrical pivot means to permit the second cylindrical pivot means to be withdrawn through the first said cylindrical pivot element from said second pivot supporting member.
 7. A mining machine as recited in claim 6 in which said second pivot means includes a pivot pin extending through the second said cylindrical pivot element towards the center of the main frame to pivotally engage said conveyor independently of said gathering head and the second said cylindrical pivot element.
 8. A mining machine as recited in claim 7, the first said cylindrical pivot element is fixedly secured to said first pivot supporting member, the second said cylindrical pivot element is fixedly secured to said gathering head, and means to pivotally support the second said cylindrical pivot element in said second pivot support member.
 9. A mining machine as recited in claim 8, said pivot pin is fixedly secured to the second said cylindrical pivot element, and means between said pivot pin and said conveyor to pivotally support the conveyor on the pivot pin.
 10. A mining machine as recited in claim 6 including means disposed between the main frame and said mining head to move the mining head upwardly and downwardly by pivoting the mining head about said common transverse axis, means disposed between the main frame and said gathering head to move the gathering head upwardly and downwardly by pivoting the gathering head about said common transverse axis, and means disposed between the main frame and said conveyor to move the conveyor upwardly and downwardly by pivoting the conveyor about said common transverse axis.
 11. A mining machine having a mining head at the front end thereof for cutting and breaking material from a mine face, a gathering head at the front end of the mining machine and below the mining head for gathering the material that is cut and broken from the mine face, a conveyor that extends from the gathering head rearwardly through the mining machine to receive the mined material from the gathering head and to convey the mined material to the rear of the mining machine and to discharge the material therefrom, a main frame for the mining machine, propulsion means on the main frame to advance the mining machine into the mine face, a pivot structure on said main frame for mounting and supporting the mining head, the gathering head and the conveyor on the main frame for pivotal movement of each of the mining head, the gathering head and the conveyor on said pivot structure and about a common transverse axis, said pivot structure including a pair of outer upright pivot supporting members on said main frame, first pivot means for said mining head which engage said outer upright pivot supporting members, said pivot structure including a pair of inner upright pivot supporting members on said main frame, second pivot means for said gathering head and said conveyor which engage said inner upright pivot supporting members, said first pivot means and said second pivot means have a common axis, and either said first pivot means or said second pivot means may be removed from said pivot structure while the other pivot means remains engaged with the pivot structure.
 12. A mining machine as recited in claim 11, in which each of said outer upriGht pivot supporting members has a circular opening to receive said first pivot means, each of said inner upright pivot supporting members has a circular opening to receive said second pivot means and said circular openings in said outer upright pivot supporting members and said inner upright pivot supporting members are coaxial on said common axis.
 13. A mining machine as recited in claim 12, in which said first pivot means includes a pair of cylindrical pivot elements, each of said cylindrical pivot elements extends inwardly through the circular opening in an outer upright pivot member and is supported at one end on an inner upright pivot support member, said mining head including a boom with a pair of parallel arms, and each of said arms has a circular opening which engages one of said cylindrical pivot elements between an outer upright pivot support member and an inner upright pivot support member.
 14. A mining machine as recited in claim 13, in which each of said cylindrical pivot elements is rigidly secured to an outer upright pivot support member, and including means to pivotally mount said boom arms on said pair of cylindrical pivot elements.
 15. A mining machine as recited in claim 13, in which said second pivot means includes a pair of cylindrical pivot elements, means to pivotally mount each of the second said cylindrical pivot elements in a circular opening in one of said inner upright pivot support members, and means to attach said gathering head to each of the second said cylindrical pivot elements.
 16. A mining machine as recited in claim 15, in which said second pivot means includes a pivot pin, each of the second said cylindrical pivot elements includes a circular bore to receive one end of said pivot pin, and means to pivotally mount said conveyor on said pivot pin independently of said gathering head and the second said cylindrical pivot elements.
 17. A mining machine as recited in claim 16, in which each of the first said cylindrical pivot elements has a bore which is coaxial with the second said cylindrical pivot elements, and said bore in each of the first said cylindrical pivot elements is greater in diameter than said pivot pin to permit said pivot pin to be withdrawn from the pivot structure through one of the second said cylindrical pivot elements and one of the first said cylindrical pivot elements and to permit said conveyor to be removed from the pivot structure independently of the removal of said mining head, said gathering head, said first pivot means and the second said cylindrical pivot elements.
 18. A mining machine as recited in claim 17, in which said bore in each of the first said cylindrical pivot elements is greater in diameter than the second said cylindrical pivot elements to permit each of the second said cylindrical pivot elements to be withdrawn from the pivot structure through one of the first said cylindrical pivot elements and to permit said gathering head to be removed from the pivot structure following the removal of said pivot pin, independently of the removal of said mining head and said first pivot means.
 19. A mining machine as recited in claim 11, in which said outer upright pivot supporting members are positioned on opposite sides of the center of said main frame, said inner upright pivot supporting members are positioned on opposite sides of the center of said main frame, and a lateral member joins one of said inner and outer upright pivot supporting members on the same side of the main frame. 